首先在您的代码中进行这些更改

First make these changes in your code

singleChildDictionary["distanceInMiles"] = distanceInMiles

然后您可以按以下方式对其进行排序:

Then you can sort it like this:

self.usersArray = self.usersArray.sorted {
        !($0["distanceInMiles"] as! Double > $1["distanceInMiles"] as! Double)
}